1. Field Of The Invention
This invention lies in the field of compatibilized polyester polyol resin prepolymer blend compositions, to techniques for making and using the same, and to the products made therewith.
2. Prior Art
In my above identified copending U.S. patent application there is described a new and very useful class of aromatic ester polyols which are useful as intermediates for reaction with isocyanates to produce cellular polyurethane and polyisocyanurate polymers. Such ester polyols are prepared from phthalic anhydride bottoms by reacting such with polyol under liquid phase conditions, all as taught in such copending applications, whose entire disclosure is incorporated hereinto by reference.
Such polyester polyols which result from so esterifying phthalic anhydride bottoms with aliphatic polyols are useful in the manufacture of cellular polyurethane and cellular polyisocyanurate polymers. Such polymers are manufactured by reacting polyfunctional organic isocyanates with such polyester polyols in the presence of a blowing agent and (usually) a catalyst.
As those skilled in the art appreciate, it is common in the foam art to prepare resin blends (sometimes also called resin precursor blends) which typically comprise homogeneous mixtures of polyol blends, blowing agent, polymerization catalyst, and, optionally but preferably, cell stabilizing surfactant. By the term "resin blend" or "resin prepolymer blend" as used herein conventional reference is made to a liquid composition which is reactive with isocyanates in the presence of blowing agent to produce a polyurethane or polyisocyanurate foam.
Particularly because of the amount of fluorocarbon blowing agent commonly used in a resin precursor blend, a problem in compatibility between the polyol (especially aromatic polyester polyols) and such fluorocarbon may arise. Unless the polyol and the fluorocarbon blowing agent are compatible with one another, optimized product foam properties may not be achieved. While sometimes a blend of different polyols in a single resin precursor blend can overcome fluorocarbon compatibility problems, such compatibility problems are preferably overcome by adding a compatibility agent to the resin precursor blend. The compatibility agent functions to compatibilize the polyols and fluorocarbon blowing agents so that homogeneity results in a product resin precursor blend as desired in order to produce foams of uniform quality and desired characteristics.
Certain monofunctional hydroxyl terminated nonionic surfactants, such as, for example, polyethoxylated alkyl phenol nonionics that contain not more than about 15 moles of condensed ethylene oxide per molecule, and thus which have molecular weights substantially below about 900, are believed to have been heretofore used as compatibility agents for certain polyol/fluorocarbon blowing agent resin precursor systems, for example, systems of the type wherein the polyol is a polycoarbomethoxy-substituted) diphenyl or a benzyl ester (such as is commonly available commercially under the trademark "Terate" from Hercules Inc.
Also, a class of amide diols is disclosed in Koehler et al U.S. Pat. No. 4,246,364 as being useful compatibility agents for blends of such polyols with fluorocarbon blowing agents, particularly when material of such class of amide diols is employed at the relatively high rate from about 20 to 85 weight percent (apparently on a 100 weight percent total polyol blend composition weight basis). When such a large quantity of amide diol is employed, the cost of resin prepolymer blend increases (because of the cost of the amide diol).
The polyester polyols prepared by esterifying phthalic anhydride bottoms with aliphatic polyols (as described in my aforereferenced copending U.S. patent application) are characteristically black-colored liquids. No way is known at present for measuring compatibility between such polyester polyols and fluorocarbon blowing agents added thereto other than by the procedure of reacting a composition of such polyester polyol and fluorocarbon blowing agent with isocyanate to produce a cellular foam products whose properties can then be observed and measured. Based upon such a foam conversion procedure, it has been determined that the properties of product foam are substantially improved when a starting resin precursor blend of such a polyester polyol and fluorocarbon blowing agent is formulated with certain compatibility agents.